Do we have a runaway workflow here or something anyone seen this error before?
Not necessarily. Are the LDF files truncated when the database is being backed up?
Can you run a SQL report to get the disk usage by table for each database?
The software doesn't write to the log file, it writes to the database and transactions are logged by SQL. If you have the database set to simple mode, SQL will maintain the log automatically. If you have it set to Full, then you must maintain the log yourself and usually your backup software will do this for you since Full mode is made for complex backup scenarios and the log must be managed as part of the backup plan.
Usually this means your using Full mode without using that type of backup, or your backups are failing.